FORM 6-K

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                        Report of Foreign Private Issuer

                    Pursuant to Rule 13s - 16 or 15d - 16 of
                      the Securities Exchange Act of 1934

                           For the month of July 2006


                                  Acambis plc
                (Translation of registrant's name into English)

                           Peterhouse Technology Park
                               100 Fulbourn Road
                               Cambridge CB1 9PT
                                    England

                    (address of principal executive offices)

    (Indicate by check mark whether the registrant files or will file annual
                 reports under cover of Form 20-F or Form 40-F

                         Forms 20-F X     Form 40-F

  Indicate by check mark whether the registrant by furnishing the information
     contained in this Form also thereby furnishing the information to the
                Commission pursuant to Rule 12g3-2(b) under the
                       Securities Exchange Act of 1934).

                              Yes       No X

 (if "Yes" is marked, indicate below the file number assigned to the registrant
                   in connection with Rule 12g3-2(b): 82- ).




Enclosure:

Directorate Change


Peter Fellner to become new Chairman of Acambis


Cambridge, UK and Cambridge, Massachusetts - 12 July 2006 - Acambis plc
("Acambis") (LSE: ACM, NASDAQ: ACAM) announces that, effective from 1 October
2006, Alan Smith will retire as Chairman, and from the Board, of Acambis and
will be succeeded by Dr Peter Fellner.

Alan Smith, 61, has been Chairman of Acambis since May 1999, having joined the
Board as a Non-executive Director in November 1995. During his tenure as
Chairman, he has overseen the development of Acambis from a small research and
development organisation into an international vaccine company capable of taking
a product through all the stages of development to licensure. Mr Smith announced
in May that, based on good corporate governance guidance that a director should
reside on a board for no more than 10 years, he would be standing down later in
2006.

Dr Peter Fellner, 62, joined the Acambis Board as a Non-executive Director in
February 2006. He was Celltech's Chief Executive Officer from 1990 to 2003 and
Chairman from 2003 until its acquisition by the biopharmaceutical company, UCB
SA, in 2004. He is Chairman of two other UK biotechnology companies, Vernalis
plc and Astex Therapeutics Limited, and a Non-executive Director of QinetiQ
Group plc, Evotec AG and Bespak plc. He is also a member of the UK Medical
Research Council.


Alan Smith said:


"I have been privileged to be involved with Acambis as it has grown into the
company it is today. It is a company with a great future and in handing over to
Peter Fellner I know that I am leaving it in very good hands. I wish Peter,
Gordon and the whole team every success in the future."


Gordon Cameron, Chief Executive Officer of Acambis, commented:


"Alan has been a source of invaluable guidance and support throughout a period
of remarkable change and growth for Acambis. The Board and I wholeheartedly
thank Alan for his contribution to Acambis' development over the years. We are
delighted that Peter has agreed to become non-executive Chairman of Acambis.
With his extensive knowledge and experience in the biotechnology industry, we
believe his insight and advice will be invaluable as we drive the continued
development of Acambis."


Peter Fellner said:


"Acambis is a high-quality company that has successfully developed into a UK
leader in the vaccine field. I very much look forward to working with the Board
and management to building Acambis further into a major biotechnology company."


                                     -ends-


Enquiries:


Acambis plc
Gordon Cameron, Chief Executive Officer
David Lawrence, Chief Financial Officer
Lyndsay Wright, VP, Communications and IR
Tel: +44 (0 1223 275 300


Financial Dynamics
David Yates/Anna Keeble
Tel: +44 (0) 20 7831 3113


About Acambis
Acambis is a leading developer of vaccines to prevent and treat infectious
diseases. Recognised internationally as the leading producer of smallpox
vaccines, Acambis is developing an investigational smallpox vaccine, ACAM2000,
and is manufacturing emergency-use stockpiles of this investigational vaccine
for the US Government and other governments around the world. It is also
developing an attenuated smallpox vaccine, MVA3000, under contracts with the US
National Institutes of Health. Acambis' US-based subsidiary Berna Products
Corporation markets Vivotif(R), the world's only licensed oral typhoid vaccine,
in North America. Acambis' investigational vaccine against Japanese
encephalitis, ChimeriVax-JE, is undergoing Phase 3 clinical testing. It also has
the most advanced investigational vaccine against the West Nile virus, which has
spread to 48 US States in the last seven years, and a vaccine against
Clostridium difficile bacteria, a leading cause of hospital-acquired infections.


Acambis is based in Cambridge, UK and Cambridge, Massachusetts, US. Its primary
listing is on the London Stock Exchange (ACM) and its shares are listed in the
form of American Depositary Receipts on NASDAQ (ACAM). More information is
available at www.acambis.com.


"Safe Harbor" statement under the Private Securities Litigation Reform Act of
1995:

The statements in this news release that are not historical facts are
forward-looking statements that involve risks and uncertainties, including the
timing and results of clinical trials, product development, manufacturing and
commercialisation risks, the risks of satisfying the regulatory approval process
in a timely manner, the need for and the availability of additional capital. For
a discussion of these and other risks and uncertainties see "Risk management" in
the Company's 2005 Annual Report and "Risk factors" in its Form 20-F, in
addition to those detailed on the Company's website and in the Company's filings
made with the Securities and Exchange Commission from time to time. These
forward-looking statements are based on estimates and assumptions made by the
management of Acambis and are believed to be reasonable, though are inherently
uncertain and difficult to predict. Actual results or experience could differ
materially from the forward-looking statements.







                                      SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant Peptide Therapeutics Group has duly caused this report to be
signed on its behalf by the undersigned, thereunto duly authorized.



Date: 12 July 2006                       ACAMBIS PLC





                                        By:  /s/ Lyndsay Wright
                                             Name: Lyndsay Wright
                                             Title: VP, Communications and IR.